With a 64-player field and 16 seeds — half that of the majors — the Olympic tennis draw set up some intriguing first-round matchups.

Play opens Saturday, though many of the big names won't start their tournaments in Rio de Janeiro until Sunday. Novak Djokovic does take the court Saturday, but in doubles, not singles.

Here's what to look for on Day 1 of what is scheduled as a nine-day event — weather permitting.

DJOKOVIC DOUBLES: Djokovic, a 12-time Grand Slam singles champion, teams with Nenad Zimonjic for Serbia in doubles. They face Croatia's Marin Cilic and Marin Draganja in the first round Saturday.

Djokovic and Zimonjic are 6-7 as a pairing in their careers, including a first-round defeat at the 2008 Beijing Games. Djokovic has played two doubles matches this year, both with Zimonjic, and they lost each time — in Davis Cup in March and in Toronto just over a week ago in an Olympic warmup.

The 40-year-old Zimonjic is a three-time major doubles champion.

In singles, at least, Djokovic has dominated Cilic, the 2014 U.S. Open champion, winning all 14 of their meetings.

Cilic is scheduled to play twice Saturday, opening his singles tournament with a potentially tough matchup in Grigor Dimitrov. Two years ago, Dimitrov made his first Grand Slam semifinal at Wimbledon at 23, seemingly a harbinger of big things to come for the player nicknamed "Baby Fed" — as in Federer.

A first-time major champion did indeed break through at the next Grand Slam tournament, but it was Cilic, who is seeded ninth in Rio. Dimitrov, meanwhile, hasn't made it past the fourth round at a major since, and his ranking is down to 34th.

VENUS RISING: It's been 16 years since Venus Williams won her singles gold medal at the Sydney Games. At 36, she's rolling into Rio with her best results in more than half a decade.

The older Williams sister is No. 6 in the world — her best ranking since early 2011. And she's coming off a semifinal appearance at Wimbledon — her deepest run at a major since the 2010 U.S. Open.

Williams faces 62nd-ranked Kirsten Flipkens of Belgium, a 2013 Wimbledon semifinalist, in the first round Saturday on Center Court. The Williams sisters open their bid for a fourth Olympic doubles gold medal Sunday.

FALLING STARS: For Sloane Stephens and Eugenie Bouchard, one player will move on Saturday with a chance for a momentum-building run in Rio. The other will see her tournament end in singles after one match.

At times in recent years, Stephens and Bouchard have each looked poised to crash the top of the rankings, but it has yet to happen. Stephens, a 23-year-old American, stunned Serena Williams to reach the 2013 Australian Open semifinals; Bouchard, a 22-year-old Canadian, was the runner-up at Wimbledon the next year.

But neither is even seeded in Rio — with Stephens ranked 22nd and Bouchard 39th.

Ninth-seeded Carla Suarez Navarro of Spain gets a tough first-round matchup against 26th-ranked Ana Ivanovic, the 2008 French Open champion.